Experimental demonstration of the amplification of electrostatic ion-cyclotron waves in a plasma with parallel ion flow shear but no magnetic-field-aligned electron current is presented. Waves with frequencies near the ion gyrofrequency and multiple harmonics launched from an antenna are observed to grow in amplitude in a region of ion flow shear. Amplification of multiple cyclotron harmonics w...

The propagation of shear waves differs between geo-media due to layer’s structure and irregularity present in different layers. This paper studies the propagation of shear waves in a monoclinic layer with irregularity lying between two isotropic semiinfinite elastic medium. The displacement in the monoclinic layer is obtained by using perturbation technique. Then the dispersion relation is foun...

We review recent results obtained in [14] on weak turbulence of shear-Alfvén waves in the limit of strongly anisotropic pulsations that are elongated along a strong external magnetic field. The kinetic equation for energy is presented at the level of three-wave interactions. It is in agreement with the Galtier et al. [13] formulation of the full three–dimensional helical case when taking the pr...

Stratified hydrostatic fluids have linear internal gravity waves with different phase speeds and vertical profiles. Here a simplified set of partial differential equations (PDE) is derived to represent the nonlinear dynamics of waves with different vertical profiles. The equations are derived by projecting the full nonlinear equations onto the vertical modes of two gravity waves, and the result...

[1] A time domain Boussinesq model for nearshore hydrodynamics is improved to obtain the conservation of vertical vorticity correct to second order and extended for use on an open coast using longshore periodic boundary conditions. The model is utilized to simulate surface waves and longshore currents under laboratory and field conditions. Satisfactory agreement is found between numerical resul...

Assessment of the rupture risk of plaque is commonly made via imaging of the lumen reduction. However it is known that this is an imperfect criterion and that other features, such as plaque stiffness, may be more relevant. Magnetic Resonance Elastography (MRE) estimates the stiffness of tissues using inversion algorithms applied to the displacement of the tissue, measured in response to the ind...

One of the most common biological composites is wood material. This natural orthotropic like material is characterized by a high anisotropy determined by the special disposition of the microstructure elements. The anisotropy of wood can be described in various ways using the values of ultrasonic velocities of bulk waves (longitudinal and shear) observed on the velocity surface deduced from the ...

A new seismic model of the three-dimensional variation in shear velocity throughout the Earth's mantle is presented. The model is derived entirely from shear bodywave travel times. Multibounce shear waves, core-reflected waves and SKS and SKKS waves that travel through the core are used in the analysis. A unique aspect of the dataset used in this study is the use of bodywaves that turn at shall...

The somewhat counter-intuitive effect of how stratification destabilizes shear flows is reexamined, in what we believe to be the simplest example, in terms of action-at-a-distance interaction between ‘buoyancy-vorticity gravity wave kernels’. The setup consists of an infinite uniform shear Couette flow in which the Rayleigh-Fjortoft necessary conditions for shear flow instability are not satisf...

[1] Radiating shear and Rayleigh waves from supershear ruptures form Mach waves that transmit large-amplitude ground motion and stresses to locations far from the fault. We simulate bilateral ruptures on a finite-width vertical strike-slip fault (of width W and half-length L with L W) breaking the surface of an elastic half-space, and focus on the wavefield out to distances comparable to L. At ...